Process for extruding plastic masses onto sheets



April 11, 1939. A. KAMPFER 2,154,333

PROCESS FOR EXTBUDING PLASTIC MASSES ONTO SHEETS Original Filed April23, 1936 2 Sheefcs-Sheet 1 Inventor:

' April 11, 1939. A. KAMPFER 2,154,333

PROCESS FOR EXTRUDING PLASTIC MASSES ONTO SHEETS Original Filed April23, 1936 .2 Sheets-Sheet 2 j; lei: a Z /5 J8 5 7 I I 9/3 la 3 In I, b 752 5 2\ ea /5 7 "3 g E Q,

EWJ AM W RU Em Inveniorv 30 stress.

3 tion of pressure and 65 methods of extruding it and Patented Apr. 11,1939 UNITED STATES PATENT OFFICE PROCESS FOR EXTRUDING PLASTIC MASSESONTO SHEETS Adoli Kampier, Charlottenbnrg, Berlin, Germany Originalapplication April 23,

January 31, 1936 1936, Serial No.

Divided and this application September 14, 1937, Serial No.

163,866. In Germany 6 Claims. (CI. 18-57) 6 windows and wind-shields ofautomobiles.

More particularly this invention, which is a division of my applicationfor patent, Ser. No. 76,046, filed April 23, 1936, relates to a methodof coating transparent sheets or plates with either 10 thin films orrelatively thick layers of highly and permanently elastic polymerisationproducts of the character particularly disclosed and claimed in myapplication for patent, Ser. No. 76,044, filed April 23, 1936.

The material produced by the method disclosed in my application, Ser.No. 76,044 is a high molecular weight polymerisation product ofunsaturated organic initial compounds which are not plastic at ordinarytemperatures and which,

even when subjected to a maximum stress of tension, expansion orpressure, immediately after the release of said strain or stress, againassume their original form or shape. Such products are obtainedpreferably by carrying the polymerisa- 25 tion to or nearly to the finalstage in the presence of certain organic admixtures. The product soformed is not solid in the technical sense of the word but is in theform of a gell or is thixotropic or is, in other words, flowable undermechanical Because of the elasticity of this polymerisation product, itis not capable of being granulated, splintered or pulverized.

This material, however, while normally not plastic, may be renderedplastic by the applicathe simultaneous application of heat withincertain definite limits. Within theselimits of heat, the polymerisedmaterial may be extruded under pressure through relatively narrow slotsonto glass supports or plates 40 and either in the form of thin films orrelatively thick layers, such relatively thick layers being particularlyadapted, because of the elasticity of the material, that is, its elasticresistance to compression and its return to its former condition 46 uponrelief of compression, to the formation of laminated glass.

I am aware that it has been proposed to produce thin sheets or foils byejecting solutions of cellulose derivatives through a slot and deposit-50 ing a sheet or foil on a sheet of glass carried past the outlet ofthe extruder or winding such sheet or foil on a roller. The highlyelastic polymerisation product disclosed in my application, Ser. No.76,044 previously referred to requires special applying it to thecondition in extruder.

In order to understand the process, it is best to first disclose anapparatus whereby the process may be carried out, this apparatus formingthe subject-matter of my application for patent, Ser. No. 76,046, filedApril 23, 1936, of which the instant application is a division.

In the accompanying drawings:

Fig. 1 is a side elevation of the apparatus used by me for the purposeof extruding my polymerisation product onto glass sheets.

. Fig. 2 is a vertical section through the press box of the machine andthrough the plunger as illustrated in Fig. 1.

Fig. 3 is a section on the line 3-3 01' Fig. 2.

Fig. 4 is a vertical section through a modified form of press box andplunger.

Fig. 5 is a section on the line 5-5 of Fig. 4.

Fig. 6 is a section,on the line 6-6 of Fig. 2.

By referring to the drawings and particularly to Fig. 1, it will be seenthat the apparatus includes a supporting pressure chamber or press box2. Operating in this pressure chamber is a plunger designated generally3. The highly polymerised mass, which as before stated, is not in aliquid or semi-liquid condition but is in a thixotropic form or gel, isplaced within the chamber 4 defined by the walls 2. The interior space 4of the chamber 2 is uniformly divided by one or more transverse walls 6.Three of such walls are shown in Fig. 2 and only one wall 6 in Fig. 4.These transversely extending walls 6 extend down from the upper edge ofthe chamber 2 but terminate short of the bottom of the chamber, asclearly shown in Figs. 2 and 4. The bottom of the chamber is formed witha relatively wide opening 5 extending transversely across the chamber.The plunger 3 has a head at its lower end which is formed to provide aplurality of transversely extending extensions or walls 1 which fitwithin the spaces defined by the end walls of the chamber 2 and thetransverse walls 6.

' The purpose of providing the transverse walls 6 is to provide meanswhereby the polymerised material within the space 4 may be continuouslyheated to a definite amount. To this end, these transverse walls 6 areformed with a plurality of passages 8 so that steam or other highlyheated frame I which supports a fluid may be caused to circulate throughthese passages. The ends walls (but not the side walls) of the chamber 2or press box are also formed with transverse passages 8 and the bottomof the chamber 2 has any desired number of transverse passages 8. 'Thusthe material within the space 4 below the plunger may be kept in highlyheated condition. While I have shown passages whereby steam or otherheating fluid may be caused to circulate through the passages 8 and 8,it is to be understood that other means, as for instance, electricalmeans, might be used for heating the end walls, transverse walls andbottom wall oi! the chamber 2. The side walls of the chamber 2 are notintended to be heated though they may be heated to a limited extent sothat no temperature fall may occur.

Attached to the bottom of the chamber 2 in any suitable manner is onesection 9 of an extruder mouth. The upper inner face of this section 9is cut away to form one-half of a transversely extending slot-like mouthIII which opens into the opening 5. The section 9, as shown in Fig. 6,is somewhat U-shaped in cross-section. Opposed to the section or jaw 9and attached to the bottom of the chamber 2 on the opposite side of theopening 5 is a depending supporting member Ii which is also formed atits upper end to provide the other half of the opening l0. That face ofthe member H which confronts the jaw or section 9 is cut away at I2.These sections 9 and H are held in place by screws l3 or other suitablemeans can be used. Disposed within the recess I2 is a jaw l4 havingpassages 8 for heating fluid, which is adjustably mounted for slidingmovement within the U-shaped jaw 9 and toward or from the U-shaped jawto define an extruding slot I5. The upper end opens into the slot i0defined by the member II and the jaw 9. The jaw I4 is held in placeagainst dropping down out of the member H by means of vertical screwsIS, the jaw i4 being vertically slotted to receive these screws. ScrewsI! extend through the depending portion of the support I l and bearagainst the outer face of the jaw l4. By releasing the pressure of thescrew l6 and then turning in the screws H, the jaw I4 may be shiftedinward toward the jaw 9 or permit it to move outward away from the jaw 9to thus control the width of the extrusion slot l5. After the jaw M hasbeen adjusted properly, the screws iii are tightened so as to hold thejaw M in its adjusted position against any possible movement.

The jaw 9 is provided with transversely extending passages 8 similar tothe passages 8 in the jaw 14 and these passages 8 and 8 are adapted tobe connected to any source of heating fluid so that these jaws are keptat the requisite temperature. The structure shown in Figs. 4 and 5 isthe same as that shown in Figs. 2 and 3, except that only onetransversely extending cross-bar or wall 6 is used in the chamber 2 andthe plunger has two depending portions or extensions 1 operating one oneach side of the crossbar or wall 6. Otherwise than this, the structureshown in Fig. 4 operates exactly the same as the structure shown in Fig.2.

In order to extrude the heated and plastic polymerisation productdirectly upon the glass plates while the foil, sheet or layer beingextruded retains its inherent heat and adhesiveness, it is necessarythat the glass plates to be coated shall be moved transversely to thedirection of movement of the mass being extruded from the press and at adistance from the underfaces of the jaws 8 and M, which is about equalto the thickness or the extruded foil or layer, so that the material, asit is extruded, comes into immediate contact with the glass plates,which plates are preferably preheated, and the ex truded mass is bent atright angles to the direction or the slot It by the moving glass platesand is carried therewith.

For the purpose of moving the glass plates beneath the extruder, I haveillustrated in Fig. 1 continuous bands l8, these bands being of fabricand passing over a series of rollers l9. Any suitable means may be usedfor causing the movement of the endless bands 3 so as to carry the glassplates beneath the slot l5. Heating devices 20 may be disposed betweenthe bands for preheating the plates and above these bands It and forwardof the chamber 2 there may be provided means designated 2!, as showndiagrammatically in Fig. 1 whereby an adhesive having a high boilingpoint may be deposited upon the upper faces of the glass plates in theform of an extremely thin foil or fllm.

With the apparatus as illustrated in Fig. 1, the preheated glass platesA are carried successively beneath the extruding slot i5 while theplunger of the press is being forced downward to extrude the polymerisedmaterial in plastic form onto the sheets of glass. Attention is herecalled to the fact that the extruding slot I5 is of considerable depthfrom top to bottom and that it is defined by two heated walls, namely,the jaw I4 and the jaw 9. By this means, the layers or foils beingextruded are shaped in the interior of the slot l5 so that after leavingthe slot, the foil or layer does not have any tendency to expand afterextrusion. It is reiterated that the distance from the upper face of theglass plates and the under faces of the jaws 9 and I4 is approximatelyequal to the thickness of the extruded sheet, foil or layer so that thelatter, immediately after extrusion, comes into contact with the glassplates and is bent at right angles to the extrusion slot by these platesand carried therewith and that the lower end faces of the jaws 9 and i4cooperate to force the film or layer into intimate contact with theglass plates and that this drives away the air between the layer or foiland the glass plates and prevents the occluding of bubbles of air orareas of air between the mass and the plates and, of course, whereadhesive is applied to the plates prior to passing the discharge slot,the form of the lower ends of the jaws 9 and 14 will act to force theextruded film or layer into close adherent contact with said adhesive.With the apparatus illustrated in the drawings, the heated mass isextruded continuously onto a series of glass plates and the compoundsheet so formed may be divided by any convenient cutting means when theplates have been carried clear of the press.

It is also to be particularly noted that the polymerised productproduced by the process disclosed in my application, Ser. No. 76,044,can be rendered temporarily plastic by the application of heat andpressure. This heat, however, must be a uniform heat to about C. but notabove 133 C. At this temperature, the polymerisation product, which asbefore remarked is thixotropic, is rendered so moldable that it can beextruded under pressure from comparatively narrow slots or holes. Thetemperature, however, must be uniform and the material must be kept atthis uniform temperature not only in the chamber 2 but-while passingthrough the extrusion slot itself and until it is discharged onto thepreheated glass plate. The glass plates are preferably preheated to atemperature of from 100 C. to 133 C.

It is, 01 course, to be understood that the chamber 2 is relativelynarrow or short in the direction at right angles to the direction 01 theslot I! but that the length of the chamber 2, and of course. the lengthof the plunger, is equal to the width or the glass or other plates orsheets which are to be coated with the polymerised material. There areno heating cavities or passages in the plunger or the extensions 1 ofthe plunger head nor are there any heating passages through the endwalls 01' the chamber 2 but only through the long side walls of thechamber. If the short end walls of the chamber were provided withheating elements, the mass in the vicinity of these short side wallswould be supplied with heat by contact and radiation from three sides.In view of the heat insulating qualities of the mass, a superheatingwould occur within the end portions of each chamber resulting in adetrimental discoloration oi the mass. It is for this same reason thatthe plunger is not heated.

What is claimed is:

1. A method of producing a sheet of plastic material and applying itupon a supporting element including heating a highly polymerised mass ina chamber, extruding a layer of material of uniform thickness from thechamber while maintaining the mass and that portion oi the mass which isbeing extruded at a softening temperature and simultaneously passing asupport at right angles to the direction of extrusion and beneath thechamber and at a distance from the extrusion opening 01' the chamberapproximately equal to the thickness desired for said layer.

2. A method of producing a sheet of plastic chamber to its softeningtemperature and in the extrusion slot and passing a support to which thelayer is to be applied at right angles to the direction of said slot andat a distance from the adjacent end of the slot approximately equal tothe thickness of the layer being extruded from the slot.

3. A method of producing a sheet of plastic material and applying itupon a supporting element including disposing a highly polymerised massof material having a softening temperature of at least 100 0. within achamber having a relatively deep extrusion slot, the slot having alength equal to the width 01' the supporting elev sure while maintainingwithin the chamber and within the extrusion slot a temperature of from100 C. to 133 C. and simultaneously passing the supporting elementbeneath the lower end of the extrusion slot and at right angles theretoand at a distance from the lower end of the slot approximately equal tothe width of the slot and to the thickness of the layer desired to beplaced upon the support.

4. A method of producing a sheet of plastic material and applying itupon a supporting element including disposing a highly polyiherised massof material having a softening temperature of at least 100 0. within achamber having a relatively deep extrusion slot, the slot having alength equal to the width of the supporting element upon which the sheetis to be applied, forcing the material out of said slot under pressurewhile maintaining within the chamber and within the extrusion slot atemperature of from 100 C. to 133 C. and simultaneously passing apreheated supporting element beneath the lower end of the extrusion slotand at right angles thereto and at a distance from the lower end of theslot approximately equal to the width of the slot and to the thicknessof the layer desired to be placed upon the support.

5. A method of producing a sheet of plastic material and applying itupon a supporting element including disposing a highly polymerised massof material having a softening temperature of at least 100 C. within achamber having a relatively deep extrusion slot, the slot having alength equal to the width of the supporting element upon which the sheetis to be applied, forcing the material out of said slot under pressurewhile maintaining within the chamber and within the extrusion slot atemperature of from 100 C. to 133 0., applying an adhesive having a highboiling point to the upper surface of the support and passing saidsupport beneath the extrusion slot and at right angles to the lengththereof and at a distance from the lower end of the slot approximatelyequal to the width of the slot and the desired thickness of the sheet.

6. A method of producing a sheet of plastic material and applying itupon a supporting element which includes rendering a mass of highlypolymerised thixotropic material plastic by heat suflicient to render itsoft, and extruding it under pressure through a slot whose walls aremaintained in a heated condition and which has sufflcient depth toinsure that the extruded mass shall assume permanently the shape of asheet before extrusion is completed and depositing the extruded sheet ona support moving at right angles to the length of the slot and at rightangles to the direction of extrusion at a distance from the extrusionoutlet approximately equal to the breadth oi the slot.

ADOLF KAMIPFER.

